Comparison XREAL Air 2 Pro vs Lenovo Legion Glasses

The general purpose of the glasses is specified based on which device they are to be used with:

— For PC/Console. Glasses connected during operation to an external device and receiving a video signal from this device. Most often, it is supposed to be connected to a computer or game console, but there are models that can be connected to mobile gadgets, drones, etc. In general, they provide a good compromise between accessibility and functionality, and besides, quite advanced graphics can be displayed on such glasses. On the other hand, for the full use of such models, powerful video cards are often required.

— For a smartphone. Models designed to turn a smartphone into a virtual reality device. To do this, the smartphone is installed in a special slot on the glasses so that its screen is turned towards the user's eyes; glasses themselves do not have screens. And the effect of virtual reality is achieved through the operation of smartphone sensors and (accelerometer, gyroscope) and the use of special applications created specifically for this format of work. The key advantage of glasses of this type is simplicity and low cost: most often these are purely mechanical devices, without built-in electronics (and even advanced models with additional hardware are much cheaper than other types of glasses). On the other hand, the quality of virtual reality directly depends on the capabilities o...f the smartphone, despite the fact that not all devices correctly process such content. In addition, the glasses must be compatible with the smartphone being used, and this is not always guaranteed (for more details, see “Maximum phone size”).

— For quadcopter (FPV goggles). Video glasses used to control drones and radio-controlled unmanned aerial vehicles (UAVs) to provide a first-person view. FPV goggles allow pilots to receive a video feed from a UAV camera in real time. To do this, the design of such glasses provides two separate miniature screens for each eye and complex optics to provide binocular vision. Lenses often have adjustable focal length to suit the visual apparatus and the varying needs of the pilot. Many FPV goggles are equipped with a built-in receiver and antennas to receive signals from the video camera on board the UAV, as well as control the quadcopter. FPV systems are actively used in the segment of racing drones, aerial photography, and even in combat operations. Glasses with a first-person view provide the pilot with a more complete perception of the surrounding environment and improve the controllability of the aircraft.

— Standalone device. Points that function completely autonomously and do not require the use of external devices. To do this, the design provides for its own processor, "RAM", video adapter, drive for storing content and a battery for power. Thus, with such a gadget, virtual reality becomes available literally anywhere in the world; and at a cost, such glasses are comparable to models for PC / consoles. On the other hand, the capabilities of stand-alone devices are noticeably more modest: the relatively low power of video adapters does not allow for the same advanced graphics as on PCs or consoles, the amount of internal memory is usually small, and the continuous operation time is limited by battery charge.

— For quadcopter (FPV glasses). Video glasses used to control drones and radio-controlled unmanned aerial vehicles (UAVs) to provide a first-person view. FPV goggles allow pilots to receive a video feed from a UAV camera in real time. To do this, the design of such glasses provides two separate miniature screens for each eye and complex optics to provide binocular vision. Lenses often have adjustable focal length to suit the visual apparatus and the varying needs of the pilot. Many FPV goggles are equipped with a built-in receiver and antennas to receive signals from the video camera on board the UAV, as well as control the quadcopter. FPV systems are actively used in the segment of racing drones, aerial photography, and even in combat operations. Glasses with a first-person view provide the pilot with a more complete perception of the surrounding environment and improve the controllability of the aircraft.

Resolution of built-in displays in glasses equipped with such equipment — that is, models for PC / consoles, as well as standalone devices (see "Intended use").

The higher the resolution, the more smooth and detailed the “picture” is given out by glasses, all other things being equal. Thanks to the development of technology nowadays, models with Full HD (1920x1080) screens and even higher resolutions are not uncommon. On the other hand, this parameter significantly affects the cost of points. In addition, it is worth remembering that in order to fully work with high-resolution displays, you need powerful graphics capable of playing relevant content. In the case of glasses for PCs and set-top boxes, this puts forward corresponding requirements for external devices, and in standalone models you have to use advanced integrated video adapters (which affects the cost even more).

The viewing angle provided by virtual reality glasses is the angular size of the space that falls into the user's field of view. Usually, the characteristics indicate the size of this space horizontally; however, if you need the most accurate information, this point needs to be specified separately.

The wider the viewing angle — the more the game space the user can see without turning his head, the more powerful the immersion effect and the less likely that the image will be subject to the "tunnel vision" effect. On the other hand, making the field of view too wide also does not make sense, given the characteristics of the human eye. In general, a large viewing angle is considered to be an angle of 100° or more. On the other hand, there are models where this indicator is 30° or even less — these are, usually, specific devices (for example, drone piloting glasses and augmented reality glasses), where such characteristics are quite justified given the overall functionality.

The refresh rate supported by the glasses' built-in screens, in simple terms, is the maximum frame rate that the screens are capable of delivering.

Recall that screens are provided in models for PC / consoles and in stand-alone devices (see "Intended use"). And the quality of the picture directly depends on this indicator: other things being equal, a higher frame rate provides a smoother image, without jerks and with good detail in dynamic scenes. The flip side of these benefits is an increase in price.

It is also worth considering that in some cases the actual frame rate will not be limited by the capabilities of the glasses, but by the characteristics of the external device or the properties of the content being played. For example, a relatively weak PC graphics card may not be able to pull out a high frame rate signal, or a certain frame rate may be set in the game and not provide boosting. Therefore, you should not chase after large values and points with a frequency of 90 fps will be enough.

Presence in points of own built — in accelerometer.

The accelerometer is a sensor that records the accelerations that the device is subjected to. It performs two main functions: determines the position of the glasses relative to the horizon (in the direction of gravity) and monitors jerks and tremors (however, this function is secondary in VR glasses). Such a sensor is necessary for a full-fledged "immersion" in virtual reality, so it must be provided in glasses made in the form of independent devices (see "Intended use"). But models for PC / consoles may not be equipped with an accelerometer — this means that the glasses are not designed for classic VR, but for more specific tasks (for example, controlling a drone with a first-person view).

As for models for smartphones, most of them do not have this function, since all modern smartphones are equipped with accelerometers. However, there are exceptions — high-end models designed for specific devices: in them, the accelerometer can work in conjunction with a smartphone sensor, which ensures the most accurate image positioning.

The presence in the glasses of its own built-in gyroscope.

The gyroscope captures the direction, speed, and angle of rotation of the device—usually along all three axes. Without such a sensor, it is impossible to achieve a full-fledged "immersion" in virtual reality, so it is available in all standalone glasses, as well as in most models for PC / consoles (see "Intended use"). In the second case, the only exceptions are individual models with a specific purpose — "personal cinemas", glasses for piloting drones, etc. In turn, glasses for smartphones do not initially require gyroscopes, since smartphones themselves have such sensors. However, there are exceptions here too — advanced models created for specific top-level devices: in them, the built-in gyroscope works in conjunction with the gyroscope of the connected smartphone, ensuring maximum positioning accuracy.

The presence in the glasses of the connector type USB-C. This is a relatively new type of USB port, which has a miniature size (slightly larger than microUSB) and a convenient double-sided design that allows you to connect the plug in either direction. It can be found in glasses for various purposes and, accordingly, provide different ways of application. So, in models for PC / consoles, this connector is used similarly to traditional USB — with the main connection, in parallel with the HDMI or DisplayPort video interface. In standalone devices, on the other hand, USB-C is mainly used to charge the battery and connect to a computer for direct file exchange, settings management, firmware updates, etc.

Also note that this paragraph may specify the USB version, which corresponds to the USB-C connector. Nowadays, two versions are relevant — 3.2 gen 1 and 3.2 gen 2; for VR glasses, the difference between them is generally not fundamental.

The type of control provided in the design of the glasses.

Note that in this case we are talking exclusively about our own controls installed directly on the body of the glasses; many models are equipped with external controllers (see "Remote control"), but they are not taken into account in this case.

- Button. Control with classic buttons. The main advantage of this option is simplicity and low cost, while its functionality is quite enough to work with basic functions like menu navigation. On the other hand, the buttons require some effort when pressed, which can be somewhat inconvenient, especially when using the controls intensively. However, most often this disadvantage is still not fundamental.

- Touch. Control using sensors that are sensitive to touch and do not require pressing (unlike buttons). In the simplest models, these are separate sensors, the functions of which are similar to the same buttons. In more advanced devices, entire touch panels can be provided, for example, allowing you to control the cursor visible through the glasses and use special gestures. Anyway, this type of control is more advanced than push-button, however, it is more expensive, and therefore less common.